Method and apparatus for die rolling



Aug. 12,-1930. wQH. DONNER AND APPARATUS FOR DIE ROLLING METHOD FiledJune 4. 1927 2 Sheets-Sheet l INVENTOR Aug. 12, 1930. v w. H. DOQNNER- v1,772,538

IE'i'HOD AND APPARATUS FOR DIE ROLLING Filed June 4, 1927 2 Sheets-Sheet2 Patented Aug. 12, 1930 UNITED STATES WILLIAM H. BONNER, OF BUFFALO,NEW YORK METHOD AND APPARATUS FOR DIE ROLLING Application filed June 4,1927. Serial No. 196,512.

This invention relates to the rolling of articles the cross sectionalarea of which varies more or less throughout their length and itparticularly relates to a method of accurately die rolling such articlesand to apparatus for carrying the method into efiect.

The method of forming articles of var ing cross sectional area by dierolling has een practiced for many years and has been often resorted towhen large quantities of articles capable of being die rolled arerequired. Die rolling can only be used to advantage when the demand forthe articles justifies the necessary large outlay.

It is customary in die rolling articles to roll the same in a connectedseries from relatively long leader bars of the proper and substantiallyconstant cross section.

Where the die rolled articles (which are usually partially finishedblanks for use in the manufacture of finished articles) are of generallycircular but varying cross sectional area throughout their length, it iscustomary to use a leader bar of more or less oval section and of suchcross sectional area as to just fill after it is reduced the largestsection of the matrix portions of the die rolls.

The matrices are designed and machined or otherwise cut in the pair ofrolls forming the die roll pass.

When the leader bar is reduced in cross section during rolling toconform to the matched matrices of the die rolls an. over fill or flashis (except in exceptional cases) bound to occur along opposite sides ofthe rolled string of blanks at all those portions which are of smallercross sectional area than the lar est port-ion.

ne important item of expense in the die rolling of such articles as'herecontemplated and in addition to the cost of the rolls is the time andlaborre uired to initially set up and adjust the dra ts in the differentstands of rolls necessary to produce the leader bars of proper crosssection, to set up and obtain relative circumferential adjustment of thedie rolls to obtain matching of their matrices as well as the adjustmentof the draft of the die rolls.

Owing to this and to the fact that the die roll matrices or passesdeteriorate more or less rapidly during rolling it is advisable to havein each pair of die rolls as many passes or matrices as possible inorder to avoid frequent changing of rolls. Relatively long rolls, arethere ore necessary in order to accommodate these multiple passes.

The diameters of the rolls used in die rolling are controlled by thelengthof the blanks to be rolled and cannot, therefore, be uniform.

In die rolling some articles it is preferable to form one article duringeach revolution of the die rolls while in rollin other articles, two ormore articles may be ormed per revolution of the die rolls. Rolls ofsmall diameter have a greater extrusion effect than rolls of largediameter but rolls of small diameter necessarily spring or deflect moreunder rolling pressure than those of large diameter. Springing of dierolls interferes more or less with the securing of accurate transverseas well as length dimensions of the rolled products and occasionsvariations in the thickness of the overfill or flash which isnecessarily formed, when rolling articles that vary in cross sectionalarea throughout their length. The flash should be maintained of eventhickness adjacent the body of the blank and as thin as practicable sothat it can be removed to the bestadvantage.

It is, of course, necessary in designing the matrices of die rolls tocompensate for roll spring and when the articles to be rolled are ofvarying cross sectional area throughout their length, it is necessary totake this into account 1n calculating the roll spring as the spring willvary at different points along the lengths of the-blank being rolled.The problem, therefore, of designing a die rollpass is not the simpleproblem encountered in designing a pass for rolling sections, ofconstantcross sectional area. a

In rolling circular articles in which large variations in crosssectional area occur, the roll spring encountered during rolling of thesmaller sections of such articles causes the finished articles to bemore or less elliptical at those smaller sections. 5

It will be understood that over fill or flash is not desired, but is anecessary evil in the die rolling in a single pass of articles ofvarying cross section. he over fill or flash is generally trimmed off bymeans of trimming dies and beside this trimming, it is generallynecessary to grind off that portion of the flash which is immediatelyadjacent the body of the blank. The flash, therefore, should be keptcomparatively thin adjacent the body of the blank because in grinding itoff there is a tendency to grind a flat portion on the blank whichtendency is increased if the flash is thick.

An object of this invention is to provide a method of die rolling from aleader bar of substantially constant or uniform cross section articlesof varying cross section in the form of a connected series of blankswith the over fill or flash which necessarily occurs at portionsthroughout the length of such series of blanks as thin and as uniform inthickness adjacent the body of the blanks as is practicable in order toinsure accuracy in the length and transverse dimensions of the finishedblanks and to reduce the work required in the operation of removing theover fill or flash and the finishing of the blanks.

This, as well as other objects,.which will appear to those skilled inthis particular art, I attain b means of the method described in thespeci cation and adapted to be carried out by means of the organizedapparatus i1- lustrated in the drawings and described in thespecification.

In the drawings Fig. 1 is a view in longitudinal section of an organizedapparatus designed for the carrying out of this method. The apparatusconsists of a die roll mill provided with backing rolls of relativelylarge diameter, a pinion stand having a pair of pinions mounted in rigidbearing and of equal pitch diameter, drive connections between the standpinions and the rolls and means for obtaining relative circumferentialadjustment of the die rolls for the purpose of matching their matrices.

The four universal joints used in the drive connection are identical andthe details of construction of these joints are illustrated in Figs. 2,3 and 4.

Figs. 5, 6 and 7 are detail views of the means for obtaining relativecircumferential adjustment of die rolls.

In carrying out this invention, I preferably utilize a pair of rollseach having a number of suitable circumferential grooves or matrices,the grooves or matrices in one roll co-operating with those in the otherroll during rolling to give the proper contour to the rolled blanks.

These rolls have a constant annular velocity ratio and leader bars ofthe proper cross section when reduced by the rolls will form a connectedseries of accurately rolled articles; the number of which of course willdepend upon the length of the leader bar.

In order to control or limit the deflection or spring of the die rollswhich varies during each revolution of the rolls when rolling articleswhich vary in cross sectional area throughout their length, I oppose thevertical thrust of such rolls and I oppose this thrust immediatelyadjacent the forming grooves or matrices by rolls having their axesparallel to the forming roll axes, and in approximately the planeincluding the roll axes. I do this by mounting below the lower roll andabove the upper roll a thrust opposing or stiffening roll. These twothrust opposing rolls are so mounted with relation to the die rolls thattheir axes lie in approximately the plane including the axes of the dierolls.

The thrust preventing rolls are merely idling rolls and are driven byfrictional contact with the die rolls and being in contact with the dierolls adjacent their matrices, they so limit the deflection of the dierolls during rolling that the over fill or flash that can rarely beavoided is limited and maintained as thin as practicable and of uniformthickness adjacent the body of the blanks.

In the mill illustrated, the lower die or forming roll 8 and the upperdie or forming roll 9 are provided with grooves 10 and 11 re spectively.These grooves or matrices are machined or otherwise formed of properdesign in the surfaces of the rolls and by cooperating one with theother are adapted to forge a leader bar into a connected series ofblanks each having the required contour and dimensions.

These rolls are relatively long and are provided with roll necks whichare journaled in bearings mounted in windows in the roll housing.

Mounted in suitable bearings in the same windows and below and in linewith lower roll 8 is a thrust opposing roll 12 and mounted above upperroll 9 and in line therewith is a thrust opposing roll 13. Rolls 12 and13 are mounted in the usual manner and the ordinary means are taken toprevent their axes from crossing the axes of rolls 8 and 9.

Rolls 8 and 9 are made materially longer and in some instances smallerin diameter than the standard rolls now generally used for die rollingand a number of forming grooves or matrices as shown are cut in eachroll. The deflection limiting rolls 12 and 13 prevent undue deflectionin rolls 8 and 9 during rolling even though these rolls are made longerthan usual.

I have shown thrust opposing rolls l2 and 13 of greater diameter thanforming rolls 8 and 9, in order to make an extremely rigid rollassembly.

It will be apparent that if die rolls having a number of grooves in eachroll as those shown in the drawings were utilized without limiting thespring by the backing rolls to a negligible amount there would be morespring in the die rolls when using the grooves adjacent the center ofthe rolls than there would when using those ad acent the roll necks. Ifthis difference in roll snring for the forming grooves adjacent the rollnecks and those adjacent the center of the roll is not taken intoaccount in designing the roll matrices, the transverse as well as thelen h dimensions of articles rolled in the di erent forming grooves willbe different.

By means of utilizin the backing rolls to control the spring of tie dierolls, I am enabled to use the same calculations in laying out thematrices of all the grooves and I am tageous to drive the lower roll 8through a enabled to roll identical articles in the different forminggrooves; that is, articles havlng the same transverse and the samelength dimensions. It is preferable to have the bearings for roll 12fixed and the bearings for roll 9 adjustable so that roll 9 can bear onroll 12. The bearings of rolls 9 and 13 are adjustable and the upwardmovement of said rolls is limited by SCIBWfdOWIlS 14.

It will be seen that by such an arrangement of thrust opposing orstiffening rolls the undesirable but necessarilypresent over fill orflash can be kept comparatively thin and can be maintained of an eventhickness adjacent the body on the blank. Such a flash can be trimmedoff the blank without any-tearing or breaking effect, such as is liableto produce a rupture capable of being magnified by the 5 heat treatment,resulting in a blank of in ferior quality.

The die rolls are driven from a pinion stand having two intermeshingpinions 15 and 16 of the same pitch diameter and of the herring bonetype which is preferable. The shafts 17 and 18 of the pinions aremounted in rigid bearings in the stand 19 and shaft 17 carries a gear 20adapted to mesh with a pinion not shown, which will be driven from anysuitable source of power, preferably a vari able speed electric motor.Pinion shaft 17 is connected to drive upper die roll 9 by means of adriving connection which includes a spindle 21 two universal joints 22and 23 and a device 24 (shown in detail in Figures 5, 6

and 7) for obtaining circumferential adjustment of die roll 9 relativeto pinion 15. By this means 24, relative circumferential adjustment ofthe die rolls can be obtained for the purpose of matching theircooperating matrices.

Lower die roll 8 is driven from pinion 16 through a spindle 25 anduniversal couplings 26 and 27.

Shaft 28 of die roll 8 is made longer than shaft 29 of die roll 9 inorder that the universal couplings 22 and 26 can be horizontally offsetor staggered as shown in Figure 1. This allows the use of relativelylarge universal couplings having ample bearing surfaces.

An suitable universal couplings or jointsmay e used in the drivingconnections so long as they have ample bearing surfaces and areconstructed with the least possible play, and in Figures 2, 3 and 4, Ihave illustrated a well known type of universal coupling. which issuitable for use in this organized apparatus.

It will be'obvious that under certain circumstances universal couplings26v and 27 and spindle 25 may be done away with and shaft 28 of thelower roll 8 directly and rigidly connected to shaft 18 of pinion 16.

In most cases, it is advisable and advantwo joints lie in parallelplanes with the cor-- responding arms of the crosses in the same planes,I am able to obtain a constant angu-- lar velocity ratio of the dierolls.

Because of the fact that the adjustment device 24 for securing relativecircumferential adjustment of the die rolls is carriedby one of thepinion shafts or in other words is .carried outside or beyond theuniversal joints of the driving connections, the necessary relativecircumferential adjustment can be obtained while maintaining a constantangular velocity ratio of the die rolls. This device 24 can be locatedon either of the roll shafts 28 or 29 or on either of the pinion shafts.

While any suitabledevice may be utilized for obtainingcircumferentialadjustment of upper roll 9, it is preferable to use one in which a fineadjustment can be obtained and.

in which the motion is transmitted through relatively large contactsurfaces. The ad- Figures 5, 6 and 7 includes two coupling mend tion 32.A bore provided with suitable key Ways extendsthrough the hub and bodyportion of each coupling member to permit the member to be rigidlysecured to the end of-a shaft, in one case the reduced end 33 of pinionshaft 17 and in the other a shaft 34 formed as a part of universalcoupling 23.

The two adjacent faces of the coupling members 30 and 31 are providedwith sector shaped projections 35 and 36 formed respectively on thecoupling members 30 and 3,1. .I

The projections of the two coupling members are spaced apart and betweenthe radial faces thereof wedges are positioned which are movable towardand from the common axis of the coupling members for the purpose ofobtaining relative circumferential adjust.-

ment of the same. This relative circumfelha to the other.

jections and the concave recesses are substantially semi-circular andoffer large hearing surfaces for withstanding the stress encounteredduring die rolling. These semicircular bearing surfaces make it possibleto arrange the outer flat faces of the two parts ofthe wedge members atdifferent angles one In the construction shown screws 41 are employedfor adjusting the wedge blocks toward and from the common axis of thecoupling members. The heads 42 of these bolts are arranged withinrecesses within body member 31 and at their outer ends the screws are 5uared to receive a wrench. The screws are t readed through the bodyportions of convex projections 40. It will be obvious that the turningof the screws will produce a radial movement of thetwo part wedges. Thescrews are locked in adjusting position by means of lock nuts 43.

The coupling members 30 and 31 are held together by means of bolts 44which extend through holes in one member and slots- 45 in theothermember. Nuts 46 are provided for drawing the coupling memberstogether and slots 45 permit relative circumferential adjustment of thetwo coupling members. Nuts 46 will of course be loosened to permit thecoupling members to be adjusted and then tightened to hold the abuttingfaces of the mem-' bers in contact.

This organized apparatus having the relativel large backing rolls forthe die rolls is capalile of exerting a great pressure on the leader barwithout deflecting the die rolls except to a negligible extent. Thisallows a large portion of the leader bar to be squeezed sideways so asto produce blanks with greater differences in cross sectional areas thanis possible in die rolling apparatus as heretofore constructed. 7

Having thus described my invention, what I claim is 1. The method ofrolling from a leader bar of substantially uniform cross section aseries of blanks, each of varying cross section,

which consists in passing between die rolls having suitable grooves ormatrices formed therein a leader bar. raised to rolling temperature andin opposing the vertical thrust at approximately the section of rollingoi the cylindrical portions of said die rolls by cylindrical rollswhereby their deflection is prevented except to a negligible extent andthe transverse and length dimensions of the blanks controlled withinnarrow limits.

2. The method of die rolling blanks of varying cross sectional area andto closely accurate dimensions, which comprises passing a leader ofsubstantially regular cross section, and while at rolling temperature,between a air of rotating relatively long die rolls having peripheralmatrix grooves varying in size lengthwise of the grooves and whichgrooves are spaced apart lengthwise of the rolls, and applying thrustpressure to the, die. rolls at points adjacent the grooves in use andapproximately opposite the points of rolling contact with the leader toprovide rolling pressure and restrict deflection of the die rolls whilethe leader is being operated upon.

3. The method of die rolling blanks of varying cross sectional area andto closely accurate dimensions, which comprises passing a leader ofsubstantially regular cross section, and while at rolling temperature,beoperating matrix grooves varying in size tween a pair of rotating dierolls having cooperating matrix grooves varying in size peripherally ofthe rolls, and applying radial pressure to the rolls closely adjacentsaid grooves and approximately opposite the points of rolling contactwith the leader to provide rolling pressure and prevent deflection ofthe rolls.

4. A mill for rolling blanks, having cross sectional areas varyinglengthwise thereof, to closely accurate dimensions, which comprises apair of relatively long die rolls having in their peripheries aplurality of cooperating matrix grooves, whose size varies peripherallyof the rolls, said grooves being spaced apart lengthwise of the rolls toprovide thereon a plurality of separate rolling dies, and means forapplying rolling thrust to said rolls at points approximately oppositethe points of rolling contact with the leader in any desired groove inwhich said leader is fed and closely adjacent the particular diesoperating upon the leader, whereby deflection of the rolls will bereduced to a minimum and the flash maintained of even and smallthickness.

-5. A mill for rolling blanks having cross sectional areas varyinglengthwise thereof to closely accurate dimensions, which comprises apair of relatively long die rolls having in their peripheries aplurality of cooperating matrix grooves, whose size varies peripherallyof the rolls, said grooves being spaced apart lengthwise of the rolls toprovide thereon a plurality of separate rolling dies, and a backing rollbearing on each die roll approximately opposite the points of rollingcontact of the dies rolls with the leader, and closely adjacent theparticular dies operating upon the leader, whereby deflection of therolls will be reduced to a minimum and the flash maintained of eventhickness.

6. A mill for rolling blanks, having cross sectional areas varyinglengthwise thereof, to closely accurate dimensions, which comprises apair of rotating die rolls having cooperating matrix grooves varying insize peripherally of the rolls, and means for applying thrustresistingpressure to the rolls closely adjacent said grooves approximatelyopposite the points of rolling contact with the leader to preventmaterial deflection of the rolls.

In testimony whereof, I have hereunto su-bscribed my name this 28th dayof May, 1927.

WILLIAM H. DONNER.

